This project is a broad multifaceted program which attempts to characterize and quantify the changes in cellular and organ physiology and pharmacology which occur with advancing age. A major goal of the program is to project the findings of one discipline in terms of the meaning to the whole system by measuring a spectrum of indices of cardiac performance at several levels of integration on the same tissue samples. Thus one is better able to assign some relative value to each measured reaction or cellular event in terms of the overall control of cardiac function. Neural, pharmacological, and physiological techniques are employed extensively from a functional level, while biochemical assay techniques are used to identify cellular change. Combined into Projects Z01 AG 00025-01 and Z01 AG 00026-01 CPB.